Some farmers and scientists are questioning the sustainability of the cereal:lupin rotation in the Western Australian wheatbelt.
Being a 'tight' rotation, its continuation is constantly under threat by disease, especially lupin root rots caused by Pleiochaeta (the brown spot organism) and Rhizoctonia fungi. To control disease, some farmers have lengthened the rotation to three years, such as wheat:wheat:lupins or wheat:barley:lupins. The longer cereal phase also helps to stabilise soil against wind erosion. However, such rotations can lead to a rapid buildup of brome grass during the two consecutive years of cereals. The implications of these rotations on the severity of brome grass infestations need to be assessed carefully.
As long as brome grass persists, farmers will stay with the cereal:lupin rotation to control it. The rotation offers the best method of brome grass control; it also controls cereal root diseases, improves soil fertility, and reliability of yield. It has been shown to be a sustainable system by some farmers who have successfully completed JO cycles (20 years) of the rotation. In this article, the authors discuss the important role of the wheat:lupin rotation in the management of brome grass.
Cheam, Aik Hock; Gil, Gurget; and Zaicou, Christine
"Managing brome grass in the wheat:lupin rotation,"
Journal of the Department of Agriculture, Western Australia, Series 4: Vol. 33
, Article 3.
Available at: http://researchlibrary.agric.wa.gov.au/journal_agriculture4/vol33/iss3/3